The test-key is a test tool disposed on a chip-scribing line, and the test-key generally has a plurality of devices under test (DUT). The devices under test are all basic elements such as transistors, resistors and capacitors, so that a user can determine whether a manufacturing process is aberrant by testing the character of these basic elements.
However, the conventional test method for the test-key generally tests one device at every turn. Thus, if the amount of the devices in the test-key is large, it will influence the measuring speed.